#hot reload with useEffect?

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sleek prairie
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is there possible to do a hot reload when i change code in useEffect? without manual refresh page

lunar vineBOT
#

Hi @sleek prairie. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

#

Yes, it is possible to do a hot reload when you change code in useEffect. According to the Next.js documentation (https://nextjs.org/docs/architecture/fast-refresh#fast-refresh-and-hooks), Fast Refresh attempts to preserve the state of your component between edits. Hooks with dependencies—such as useEffect, useMemo, and useCallback—will always update during Fast Refresh. Their list of dependencies will be ignored while Fast Refresh is happening.

For example, when you edit useMemo(() => x * 2, [x]) to useMemo(() => x * 10, [x]), it will re-run even though x (the dependency) has not changed. If React didn't do that, your edit wouldn't reflect on the screen.

However, there are some cases where hot reload might not work as expected. For instance, if you're using Docker, there have been reported issues (https://github.com/vercel/next.js/issues/36774) with hot reload not working. Also, if there is content rendered through something that is not _app.js (ie. through pages/index.js), then it will hot reload as usual according to a Github issue (https://github.com/vercel/next.js/issues/53614).

If you're not seeing the changes reflected in the browser, you can use the router.reload function from Next.js's useRouter hook to manually reload the current URL. Here's an example from the Next.js documentation (https://nextjs.org/docs/pages/api-reference/functions/use-router#routerreload):

import { useRouter } from 'next/router'
 
export default function Page() {
  const router = useRouter()
 
  return (
    <button type="button" onClick={() => router.reload()}>
      Click here to reload
    </button>
  )
}
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This is equivalent to clicking the browser’s refresh button. It executes window.location.reload().

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

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@sleek prairie kapa.ai is still learning and improving, please let us know how it did by reacting below

sleek prairie
lunar vineBOT
#

Let me check the knowledge base for you. One moment! :books:

#

Yes, Next.js supports a feature called Fast Refresh that should automatically update your application in the browser when you make changes to your code, including changes in useEffect or event handlers. This feature is designed to preserve React state between updates, providing a more seamless experience during development.

However, there are some cases where Fast Refresh might not work as expected. For instance, if there is content rendered through something that is not _app.js (ie. through pages/index.js), then it will hot reload as usual according to a Github issue (https://github.com/vercel/next.js/issues/53614).

If you're not seeing the changes reflected in the browser, you can use the router.reload function from Next.js's useRouter hook to manually reload the current URL. Here's an example from the Next.js documentation (https://nextjs.org/docs/pages/api-reference/functions/use-router#routerreload):

import { useRouter } from 'next/router'
 
export default function Page() {
  const router = useRouter()
 
  return (
    <button type="button" onClick={() => router.reload()}>
      Click here to reload
    </button>
  )
}

This is equivalent to clicking the browser’s refresh button. It executes window.location.reload().

If you're still having issues with hot reloading, it might be due to a bug or a specific configuration in your project. In that case, you might want to check the open issues on the Next.js GitHub repository (https://github.com/vercel/next.js/issues) or consider opening a new issue with a detailed description of your problem.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: